1. Field of the Invention
The present invention relates to a magnetic head and a method of fabricating the magnetic head, and more particularly, to a reading head in a perpendicular magnetic recording head and a method of fabricating the reading head.
2. Description of the Related Art
Magnetic recording can be classified as longitudinal magnetic recording and perpendicular magnetic recording according to a recording method. The longitudinal magnetic recording method records information using a characteristic that a magnetization direction of a magnetic layer is arranged in parallel with a surface of the magnetic layer, and the perpendicular magnetic recording method records information using a characteristic that the magnetization direction of the magnetic layer is arranged perpendicular to the surface of the magnetic layer. In view of a recording density, the perpendicular magnetic recording method can record more information than the longitudinal magnetic recording method.
A magnetic head, for performing the perpendicular magnetic recording, includes a writing head that writes information onto a perpendicular magnetic recording medium and a reading head that reads the information recorded on the recording medium.
The writing head includes a main pole, a return pole, and a magnetic coil. The main pole and the return pole form a magnetic path of a recording magnetic field that is generated by the magnetic coil, and are formed of a magnetic material such as NiFe. Also, a component ratio of each component can be adjusted to differentiate saturation flux densities (Bs) of the main pole and the return pole. The magnetic coil generates a recording magnetic field for recording the information on the recording medium. A surface of the writing head, which faces a recording layer of the recording medium, is defined as an air-bearing surface.
The reading head includes a reading sensor that is protected from an external magnetic field by a shield layer, and the reading sensor can be a giant magneto-resistance (GMR) device or a tunneling magneto-resistance (TMR) device.
Magnetic writing heads can be classified as heads including a spiral type coil structure, in which the magnetic coil surrounds the area where the main pole and the return pole contact each other from upper and lower directions, heads including a dual pancake type coil structure, in which the magnetic coil is formed to have an upper portion and a lower portion between the main pole and the shield layer, and heads including a planar coil structure, in which the magnetic coil is formed as a plane in parallel with the recording surface. The heads having the planar coil structure have a larger recording field and a higher resolution than those of the heads having other types of coil structures, and thus, can be suitable for a high coercivity medium that is required by high density recording media.
The writing head having the planar coil structure uses a planar process involving the forming of a predetermined material layer on a substrate corresponding to the planar recording medium and patterning of the material layer, and thus, the reading head that is integrally formed with the writing head should have a structure that can be planar-processed.
Due to the processing limitations of a conventional reading head formed using the planar process, the reading sensor cannot be fabricated to have a structure that directly detects the magnetism from the recording medium because the layers are stacked onto the substrate in the planar process, and thus, the reading sensor is arranged in parallel with the substrate inevitably, and the reading sensor cannot be exposed to the air-bearing surface. Due to this problem, an additional magnetic flux guide is conventionally used to transfer the flux to the air-bearing surface to the reading sensor. According to this remote sensing structure, the flux cannot be sufficiently transferred to the reading sensor because of a magnetic loss caused by the magnetic flux guide. Therefore, according to the conventional reading head, a reproducing sensitivity may be degraded by using the magnetic flux guide.